Kara should have given her a long kiss to make her forget.So Cat figured it out, and pretty quickly, too. One wonders why she didn't figure out that her coworker Clark Kent was Superman. Perhaps she didn't work as closely with him. Actually, for a moment, I thought she was going to look straight at Kara with glasses off and not recognize her as Supergirl.
(I'm worried that the fact that they didn't means they're probably going to try to backtrack Cat knowing somehow by convincing her she was wrong - which would be dumb.)